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from the SEDIMT II model, the peak stage is at 59.06 ft. (Elev. <br />O U) 6613.06). The principal spillway can adequately handle the peak <br />discharge rate of 18.88 cfs at a depth of flow of 1.86 ft. (see Table <br />8). At the peak stage (59.06 ft.) there is still approximately 1.0 <br />ft. of freeboard before the pond would reach a maxi= stage of 60.00 <br />ft., which is a conservative estimate and within the requirements for <br />a spillway to handle the runoff from a 25 -year, 24 hr storm event. <br />Therefore, the principal spillway at inlet elevation of 6611.20 will <br />also serve as the emergency spillway. In addition to handling this <br />runoff, the detention time is adequate to have a peak effluent <br />sediment concentration of 0.0 mg /l with 0.0 tons of sediment <br />discharged and 100.0 percent basin trap efficiency (see Table 7, <br />Storm Event SUMMMy Port). <br />The Wadge Itpoundment (No. 002) will remain as a permanent incised <br />impoundment after mining to compliment the postmine land use. The <br />pond will provide a dependable source of water for livestock and <br />wildlife. Appendix 7 -10, Tab 7, the Pond Abandonment Plan section of <br />Tab 13, and the Proposed Decision and Findings of Compliance Document <br />for the second renewal of Seneca II Mine Permit C -80 -005 (11/20/92), <br />contain discussions pertaining to the permanence of this facility. <br />The proposed permanent postmine Wadge Impoundment (No. 002) is shown <br />on Exhibit 7 -8A. <br />7 -6a -6 Revised 12/10/92 <br />